Pluto is a reasonably difficult object to study‚ lying beyond the orbit of Neptune (for the majority of its orbit) in the Kuiper Belt. Beyond sending a probe to the planet (which NASA did in 2015) we largely rely on stellar occultations to study the dwarf planet's atmosphere‚ when it passes in front of a bright star from our perspective.&;quot;For objects with an atmosphere‚ refraction plays an essential role to explain the drops of flux and the aureoles observed during these events‚&;quot; astronomer Bruno Sicardy explains in a 2022 paper published in Comptes Rendus Physique. &;quot;This can be used to [derive] key parameters of the atmospheres‚ such as their density‚ pressure and temperature profiles‚ as well as the presence of atmospheric gravity waves and zonal winds.&;quot;Pluto has an orbit lasting 248 years‚ meaning that it didn't even get to celebrate one Pluto year of being a planet from its discovery before it was downgraded in 2006.                                 As it orbits‚ its distance varies from between 49.3 astronomical units (AU) and 30 AU‚ with 1 AU being the average distance between the Earth and the Sun. At its farthest point from the Sun‚ average temperatures can fall as low as -233°C (-387°F)‚ while at its closest approach it can reach a balmy -223°C (-369°F). This temperature change‚ of course‚ has an effect on the planet's atmosphere.&;quot;When Pluto is close to the Sun‚ its surface ices sublimate (changing directly from solid to gas) and rise to temporarily form a thin atmosphere‚&;quot; NASA explains. &;quot;Pluto's low gravity (about 6 percent of Earth's) causes the atmosphere to be much more extended in altitude than our planet's atmosphere. Pluto becomes much colder during the part of each year when it is traveling far away from the Sun. During this time‚ the bulk of the planet's atmosphere may freeze and fall as snow to the surface.&;quot;That has been known about for some time. Since Pluto made its closest approach to the Sun‚ being closer to the Sun than Neptune between 1979 and 1999‚ it has been moving away from our Solar System's main heat source‚ and as such we would expect its atmosphere to begin to contract. However‚ until 2018 observations showed that its surface pressure and atmospheric density continued to increase‚ which scientists put down to &;quot;thermal inertia&;quot;.“An analogy to this is the way the Sun heats up sand on a beach‚” said Southwest Research Institute Staff Scientist Dr. Leslie Young in a 2021 statement. “Sunlight is most intense at high noon‚ but the sand then continues soaking up the heat over course of the afternoon‚ so it is hottest in late afternoon. The continued persistence of Pluto’s atmosphere suggests that nitrogen ice reservoirs on Pluto’s surface were kept warm by stored heat under the surface. The new data suggests they are starting to cool.”A 2020 occultation provided further evidence of this contraction of Pluto's atmosphere‚ evidence that Pluto's nitrogen continues to be sublimated on the dwarf planet as it loses its stored-up heat‚ and heads towards the Plutonian winter.